Evaluation of radiographic differences in types of impacted and erupted mandibular third molars

Introduction: Factors like mismatches between tooth and jaw sizes, the width of the ramus, and alignment of lower back teeth are thought to play significant roles in mandibular third molar impaction (M3M). Aim of the study was to evaluate the radiographic differences in angular and linear measurements between various types of impacted and erupted M3Ms. Material and Methods: Orthopantomographs and Lateral cephalograms of 300 patients aged 18-30 were included and linear measurements such as ramus height, mesiodistal width of mandibular first molar and M3M, retromolar space, the ratio of retromolar space to mesiodistal width of M3M, type of impaction were assessed on panoramic radiographs. Angular measurements, such as gonial angle, were assessed on Lateral cephalograms. Results: The study's mean values revealed statistically significant differences between impacted and non-impacted groups in terms of the above-mentioned radiographic parameters and were also significant across genders. Significant differences were found between retromolar space, mandibular first molar width, and retromolar space to M3M mesiodistal width ratio across all three levels of Pell and Gregory classification, as well as significant differences in M3M width across all four types of Winter's classification. Conclusion: The study identifies key anatomical factors such as retromolar space to M3M mesiodistal width ratio followed by retromolar space, ramus height and gonial angle to significantly influence the risk of M3M impaction. These findings enhance the ability of dental professionals to predict impaction and improve patient outcomes.